550 Access Error

Hi, we have a FTP server on vSphere on a windows 2008 server platform.
One of our Unix machines now cannot send files to it, we checked permissions etc.
Can login, when using put events.txt it gives a 550 Access Denied error.
Nothing has changed from yesterday when it was working apart from checking permissions etc etc

Check the permissions of local file. Perhaps the 'permission denied' is happening on the local side, not the remote side.

Check carefully what user you're running the UNIX ftp client under, and what permissions the relevant file and folders have.